naturebriefs
9:08in productionCh. 1 · Where they come from/ 9:08 · ceiling 15 min
Insects & invertebrates · Fungi

Leafcutter ant

They farm fungi, deploy antibiotics, and run cities underground—yet never leave the tropics of the Americas.

Leafcutter ants are fungus-farming insects endemic to tropical Americas. They cut leaves to feed domesticated fungi. Their colonies reach 3.55 million individuals across 600 m². They bite with force 2600× body weight. They co-evolved with antibiotic-producing bacteria to protect crops. They do not eat leaves. They do not occur outside their native range. They are not generalists—they depend absolutely on specific fungi and bacteria.

Insects & invertebratesFungiAgricultureEcologyEvolutionAgriculture across the network →
Chapters & takeaways5
  1. 0:58
    Where they come from

    Fifty-five species. Three genera. One continent-wide range.

  2. 1:52
    What they actually do with leaves

    They cut leaves not to eat—but to feed fungi they cannot live without.

  3. 3:09
    How big their societies get

    Nests occupy up to 600 m² and house 3.55 million individuals—second only to humans in societal scale.

  4. 4:26
    How to tell them apart

    Atta has three spine pairs and smooth thorax; Acromyrmex has four and rough—visible without magnification.

  5. 5:34
    The full symbiosis

    They farm fungi, suppress parasites with bacteria, and build subterranean cities—all obligate, all interlocked.

Worth your time?

Yes. See the whole thing.

4.5/ 5
What works
  • farms fungi
  • suppresses Escovopsis with Pseudonocardia
  • builds nests housing up to 3.55 million individuals
  • carries up to 50× body weight
What does not
  • eat leaves
  • occur outside tropical Americas
  • farm non-Lepiotaceae fungi
See it if
  • ecologists
  • mycologists
  • field observers
Skip it if
  • temperate-zone naturalists
  • solitary-behaviour researchers
  • generalist-insect studies
The written brief1 min read

What the species is and where it came from

Leafcutter ants are at least 55 species across Atta, Acromyrmex, and Amoimyrmex—endemic to South and Central America, Mexico, and parts of the southern United States.

How it works, in terms someone would actually use

They cut fresh leaves, carry them up to 50× their body weight, and feed them to domesticated fungi in vast underground nests.

What it gets right

They reliably grow fungal gardens at scale. They suppress Escovopsis with Pseudonocardia bacteria. Their caste systems and nest architecture sustain up to 3.55 million individuals in 600 m².

What it does not

They do not eat the leaves they cut. They do not survive outside tropical Americas. They do not farm any fungus but Lepiotaceae—especially Leucoagaricus gongylophorus.

What it changed

They redefined cooperation: no other animal cultivates its food, maintains monoculture, farms bacteria for crop protection, and organises labour across millions without central command.

Who it is for, and who it is not

For ecologists, mycologists, and anyone who watches ants and wonders how a colony thinks. Not for those seeking solitary behaviour, wide dispersal, or temperate-range species.

Is it worth your time

Yes—if you want to see a non-human society that builds cities, farms, defends crops, and deploys antibiotics, all in soil.

Same habitat · Insects & invertebrates4 of 23
9:16
Army antArmy ants are a functional category—not a taxon—defined by nomadism, mass raiding, and monogynous, wingless queens. Genetic evidence from 2003 shows some lineages share deep ancestry; others converged. Their raids drive ecosystem dynamics across tropical forests. They offer no compromise: no stillness, no shared queens, no permanent home.
7:56
AntlionAntlions are a globally distributed group of ~2,000 neuropteran insects (family Myrmeleontidae) whose larvae specialise in digging conical pits in dry, sandy habitats to ambush ants and other small arthropods. Larvae detect prey via vibration-sensitive thoracic hairs, inject venom through jaws, digest prey externally, and store all metabolic waste until pupation—voiding it later as meconium. A 2019 phylogenetic study confirms Myrmeleontidae is largely monophyletic, except Stilbopteryginae and Palparinae. Death-feigning behaviour increases larval survival by 20%. Adults of some species feed on pollen and nectar; others prey on small arthropods.
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Bombardier beetleA chemical weapon built into an insect. Not metaphor. Not analogy. A real, measurable, temperature-raising, pulse-firing, predator-killing system—evolved stepwise, deployed locally, observable without lab gear.
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BumblebeeBumblebees are cold-adapted, fuzzy, eusocial bees of the genus Bombus. They operate in environments where other bees fail. Their colonies are small and annual. Their decline is documented — not speculated — across Europe, North America and Asia. They are not charismatic by design, but by function: they make plants fruit when it is still cold.
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